Comparing the Effects of Aquatic and Land-based Exercises on the Bio-motor Abilities of Elderly Men

Introduction

Increased life expectancy is a human achievement worth celebrating, but the resulting population aging poses serious challenges to human societies (1). According to the United Nations, the world’s geriatric population was about 740 million in 2009, which will reach two billion by 2050 (2). Population of the Iranian elderly is expected to grow at the same rate and reach 25 million by 2050, that is, about a quarter of the Iranian population will be elderlies by that time. According to the latest national census, the Iranian elderly population has grown by 12% from 8.5 million in 2011 to 9.6 million in 2016 (1, 3). The developing Asian countries are growing old faster than the other countries. As people age, their health problems progressively increment (3). When people age past the middle-age years, they lose about 1.5% of their physical and mental functioning every year. This means that people reaching the age of seventy have lost, on average, about 26% of their abilities. Thus, most people who reach an old age struggle with many disabilities (4). Balance issues are known as the main cause of falling among the elderly; an event that frequently leads to impaired performance, dependence, and disability (5). Hence, it is imperative to develop and implement prevention and rehabilitation programs and interventions to reduce these problems among this portion of the population.

Exercise is one of the most effective ways to maintain and enhance physical abilities (6, 7). Exercise is even more important for the elderly because of physiological, pathological, and psychological changes associated with aging. In addition, appropriate exercise interventions may somewhat restore the physical abilities of older adults (6). However, the type of exercise is also very important as it needs to be relatively simple and appealing to the elderly. Complex exercise programs are likely to undermine their self-esteem, reduce output and participation, and ultimately, discourage the elderly from committing to the program (7).

The typical physical exercises and activities recommended for the elderly include resistance exercise, tai chi, yoga, and balance exercises (8). Nonetheless, as people grow older, physiological effects of aging and development of diseases such as arthritis and motor disabilities may cause them to find these exercises more challenging and less interesting (9, 10).

One of the important tasks of geriatric nursing is to promote the physical health of the elderly and one of the best ways to do so is the use of well-tested physical activities such as aquatic exercises (11). Thanks to its physical characteristics, water is the perfect environment for the physical activity of the elderly (12). Because of the water's buoyancy effect, exercising in water, which has proven health benefits, has long been a popular way of physical and mental relaxation (13, 14). Besides its well-known soothing effects, exercising in water has a wide range of physical advantages such as improved endurance, fitness, and respiratory health (15, 16). Aquatic exercises also provide a pleasant environment and an opportunity for the elderly to interact and sympathize with their peers (16). Despite the undeniable benefits of aquatic exercises for the elderly, they are also associated with the risk of musculoskeletal injuries, falling, getting cold, chlorine poisoning, and drowning. Of course, these risks can be mitigated by taking approximate measures such as provision of pools with proper safety and heating equipment and flooring, proper measurement and control of chlorine level in pool water, and recruitment of well-trained and experienced lifeguards (14, 15).

Another recommended method for the elderly to engage in physical activity is land-based exercises (17). Regular physical activity during youth and adulthood is known to prevent cardiovascular illnesses, diabetes, and other systemic diseases (18). Land-based exercises can be performed in any safe environment and provide benefits such as better nocturnal sleep, weight loss, improved mood, and enhanced flexibility (19). Cromwell et al. (2007) and Lin et al. (2006) have shown that land-based balance and functional exercises can promote walking ability (20, 21). Since the elderly may gradually lose motivation to participate in this type of exercise, the exercise program needs to be sufficiently diverse and the exercise environment must be changed before becoming repetitious to prevent disinterest and demotivation among participants (10, 22).

Only few studies have compared the outcomes of land-based and aquatic exercises. For example, the study of Noh et al. (2008) on the effects of exercise in water and on land on the balance and muscle strength of stroke survivors showed a significant improvement in balance and muscle strength of an aquatic exercise group as compared to a land-based group (23). However, the study of Rezazadeh and Baluchi (2015) revealed that aquatic and land-based exercises have the same effects on static and dynamic balance and the risk of falling among the elderly (24). Kaneda et al. (2008) also presented that aquatic and land-based exercises both improved balance ability among the elderly (25). A study by Colado et al. (2005) reported no significant difference in physiological response, heart rate, and blood lactate among the elderly after performing resistance exercise on land and in water until muscular fatigue (26).

There is a clear association between psychological traits and lifestyles of the elderly and their performance and independence (18), and thus, their ability to control the outcomes of aging and therapies. Despite the benefits of aquatic and land-based exercises for the elderly, a review of the related literature showed that only few researchers have studied the effects of these exercises on the biomotor abilities of the elderly, and even those few have mostly addressed the effects of these two methods separately. Studies that have investigated both methods in conjunction have mostly reported contradictory results and could not draw a conclusion as to which method is more effective. In view of the above gaps in the literature, this study aimed to compare the effects of aquatic and land-based exercises on the biomotor abilities of elderly men in Mashhad, Iran.

Methods

The present randomized clinical trial with two groups (aquatic exercise and land-based exercise) and a pretest-posttest design was performed from April 4 to June 4, 2017. The research population included the elderly who visited Imamat and Daneshamuz health centers in Mashhad, Iran. These health centers were chosen because of their high involvement with the elderly and better access to subjects. The study population was formed by 60 elderlies who met the inclusion criteria. The subjects were randomly selected by using the lottery method at a meeting with all candidates. The selected subjects were divided into two groups of aquatic exercise and land-based exercise. Before the study, the minimum sample size was calculated using the formula for comparing the means of two populations. To obtain the mean value of motor ability (one of the dimensions of biomotor ability), a preliminary study was conducted on 20 elderlies (10 elderlies in each group). The largest sample size was calculated for motor ability index (mean: 61.0±15.6 and 50.5±11.0 for the land-based and aquatic groups, respectively). Thus, to achieve 95% confidence level and 80% test power, the sample size was estimated at 26 (per group). Considering the possibility of sample attrition, the sample size was increased to 30 subjects per group. Nevertheless, all the subjects managed to complete the study.

The inclusion criteria were: male gender, 60 years of age or older, visual and cognitive health, and lack of osteoporosis (self-reported or recorded in the health center), skeletal, muscular, and nerve disorders (e.g., fractures, amputations, and scoliosis), any maiming or paralysis, visible inability to walk, and acute or chronic disabling diseases (e.g., myocardial infarction and cerebrovascular accident [CVA]) based on examination and health center records.

The exclusion criteria comprised of acute musculoskeletal, bone, or disabling diseases (e.g., cold) during the study, withdrawal for any reason, additional exercises (including swimming), severe physical activities during the study (directly asked at each session), absence for more than three sessions, and inability to perform exercises in more than three sessions.

The data collection instruments used in this study were a standard demographic information questionnaire and a researcher-made questionnaire entitled as “elderly biomotor ability checklist”. The demographic information questionnaire consisted of nine open-ended and multiple-choice questions about age, height, weight, body mass index, level of education, marital status, smoking, and history of previous illnesses. The elderly biomotor ability checklist consisted of three sections for recording motor abilities, flexibility, and general endurance of the elderly. This checklist was developed based on previous studies and after consultation with members of the Faculty of Nursing and Midwifery at Mashhad University of Medical Sciences (MUMS). Biomotor abilities (i.e., motor ability, flexibility, and endurance) of the subjects were evaluated using the standard and well-established methods described below. Motor abilities were measured using the Timed Up and Go (TUG) test, which relies on the time needed for the person to rise from a chair (without the help of hands), walk 3 meters, and then return to sit back on the chair (27). Flexibility was gauged using the Wells test, which involves stretching the legs in sitting position and then stretching the hands to touch the tip of the toes (28). General endurance was determined using the six-minute walk test (6MWT), which involves measuring the distance that a person can walk on a flat surface in 6 minutes (29).

The content validity of the data collection instruments was confirmed with the help of 10 members of the Faculty of Nursing and Midwifery (including gerontological specialists) at MUMS. The reliability of the tests of motor ability, flexibility, and general endurance was confirmed by the inter-rater agreement method. For this purpose, the results of 10 subjects were evaluated independently by two raters (researcher and a research assistant trained and approved by supervising and advising professors) and then compared with one another. The Pearson correlation coefficients were calculated at r=0.86 for motor ability, r=0.89 for flexibility, and r=0.83 for general endurance, which demonstrated the reliability of the instrument.

Prior to the intervention, the biomotor abilities of the subjects including motor ability (TUG test), flexibility (Wells test or stretching hand to touch the toes), and general endurance (6MWT) were measured by the researcher under the supervision of a rehabilitation medicine specialist and were recorded in the elderly biomotor ability checklist. In the TUG test, the subject was asked to rise from a chair without using hands, walk 3 meters, and return to sit back on the chair. The subject was also asked to do this as fast as possible without running. The total time of the test was recorded in the checklist. All the tests were conducted in Kazemian sports hall of Mashhad Department of Education.

After obtaining the permission of the Regional Medical Ethics committee of MUMS and presenting an introduction letter to the authorities of the health centers chosen for the study, the necessary coordinations for starting the research were made. The researcher invited the elderly who visited the health centers to attend a briefing session at a later date at the same site. In this session, after explaining the research objectives and procedure for about 15 minutes, the attendees who were eligible and willing to participate in the study were identified and asked to complete an informed consent form.

The enrolled people were randomly divided into two groups of aquatic exercise and land-based exercise based on the draw. The participants were asked to refrain from exercising, performing intensive activities, swimming, or going to a pool outside the scheduled exercise sessions. The subjects of both groups were also asked to complete a demographic-medical information questionnaire in advance. For the pre-test, the subjects of both groups were invited to Kazemian sports hall and indoor pool. The individual tests were performed by the researcher under the supervision of a rehabilitation medicine specialist.

The group sessions of aquatic exercise were held in the Kazemian indoor pool. In the first session, the researcher provided a 45-minute training, in which the subjects were taught how to walk inside the pool, hold the body straight, and keep the sacrum perpendicular to the pool floor. Aquatic exercises were performed in three 1-hour sessions per week for six weeks and under the supervision of a rehabilitation medicine specialist. The aquatic exercise program was designed based on the subjects’ condition, according to the suggestions of reliable resources (27), and with the approval of the rehabilitation medicine specialist. Each aquatic exercise session consisted of three stages: (i) warming up by slow walking (200 m) in water for 15 minutes, (ii) stretching of all joints, and (iii) walking forward, backward, and sideways on heels and on toes at 10, 15, and 25 meter distances, each exercise was repeated twice with moderate intensity (for 5 minutes; Table 1). This exercise was performed as a group activity so that it would be of the same intensity for all the subjects. It was decided that subjects who expressed inability to perform the exercise or showed excessively high heart rate (according to age) or excessively low blood pressure should be stopped and removed from the sample, but no such event occurred during the study.

The land-based exercise sessions were also held in Kazemian sports hall. The land-based exercise program was designed based on the subjects’ condition and  the recommendations of reliable sources (24) and under the supervision of the rehabilitation medicine specialist. This program consisted of four stages: (i) warming up, (ii) muscle-resistance exercises, (iii) balance exercises, and (iv) rest. The first stage, warming up, involved 10 minutes of walking, which was followed by 10 minutes of muscle resistance exercise (e.g., flexion and extension of the limbs, moving the limbs towards and away from the trunk, turning the neck and waist, and flexion and extension of the neck and waist). The third stage involved 10 minutes of balance exercise (e.g., walking forward and backward with balance, transferring weight from one foot to the other, walking on toes and heels, and standing on one foot), and the last stage of the cycle was resting (Table 2). For this group, the exercise program was implemented for six weeks, three sessions a week, each session lasting one

Table 1. Aquatic exercise program

Table 2. Land-based exercise program

hour. All the sessions were held under the supervision of a rehabilitation medicine specialist. This program was also implemented as a group activity so that it would be of the same intensity for all the subjects. Although it was decided that subjects who expressed inability to perform the exercise or show excessively high heart rate (according to the age) or excessively low blood pressure should be stopped and removed from the sample, none of these events occurred during the study. The researcher attended and supervised all the exercise sessions and provided guidance when necessary. After the intervention (at the end of the third session at the 6th week), the biomotor abilities of both groups were measured again in the same manner as explained above.

This study was conducted in full compliance with the ethical requirements of clinical research, including the acquisition of permission from the Ethics Committee of the university and obtaining written informed consent from the participants. Since holding exercise sessions for the elderly, whether on land or in water, necessitates taking some precautions to prevent injury, the researcher fully supervised all the sessions and made sure of the presence of skilled lifeguards, access to first aid equipment, and controlled temperature of both the exercise hall and the pool. The collected data were analyzed in SPSS, version 16, using descriptive statistics (for data summarization), independent t-test, paired t-test, Chi-square test, and Fisher’s exact test.

Results

The results of independent t-test showed no significant difference between the aquatic exercise and land-based exercise groups in the mean age of the subjects (69.9±5.1 vs. 68.0±5.0 years, P=0.15). Other demographic-medical characteristics of the subjects and the results regarding homogeneity of the two groups are presented in Table 3.

Table 3. Demographic characteristics of the elderly in the aquatic exercise and land-based exercise groups

*: t independent samples test

**: Exact Chi square

***: Fisher Exact

****: Chi square

At the pre-intervention stage, the aquatic exercise group had a mean score of 6.2±0.8 in motor ability, 2.1±4.0 cm in flexibility, and 602.9±103.4 in general endurance. At the same stage, the land-based exercise group had a mean score of 7.0±2.1 in motor ability, 1.2±3.4 cm in flexibility, and 547.7±142.1 in general endurance. The results of independent t-test revealed no significant difference between the two groups in terms of the mean scores of motor ability (P=0.06), flexibility (P=0.35), and general endurance (P=0.09) at the pre-intervention stage. At the post-intervention stage, however, the aquatic exercise group had significantly higher mean scores in motor ability (P=0.01) and general endurance (P=0.03) relative to the land-based exercise group. At the post-intervention stage, although the aquatic exercise group had a higher mean score of flexibility than the other group, this difference was not statistically significant (P=0.25; Table 4). There were no significant inter-group differences in

Table 4. Mean and standard deviation of biomotor indices of the elderly in the aquatic exercise and land-based exercise groups at the pre- and post-intervention stages

*: t independent test

**: Mann-Whitney test

terms of changes in the mean scores of motor ability (P=0.18) and flexibility (P=0.42), but such difference was significant in terms of general endurance (P=0.001). The results of t-test signified that in both groups, mean scores of motor ability, flexibility, and general endurance were significantly improved after the intervention compared to the corresponding values prior to the intervention (P<0.001).

Discussion

According to the results, the elderly who participated in the aquatic exercise program experienced higher improvements in motor ability and general endurance than those who exercised on land. However, both types of exercises boosted flexibility to the same extent.

A study by Noh et al. (2008) on the effects of aquatic and land-based exercises on balance and muscle strength of stroke survivors showed higher improvement in balance and muscle strength in the elderly who exercised in water than in those who exercised on land (23). Although the present study investigated motor ability, general endurance, and flexibility, which are different from the parameters studied by Noh et al. (2008), since muscle strength and balance are likely to be associated with motor ability, their results can be considered consistent with ours in this regard. On the contrary, Rezazadeh and Baluchi (2015) reported that aquatic and land-based exercise programs both had the same positive effects on the elderly’s static and dynamic balance and risk of falling (24). Despite the difference in the studied parameters, these results can be considered consistent with our findings regarding the effects of aquatic and land-based exercises on flexibility, but not concerning the impact of these exercises on motor ability and general endurance.

Kaneda et al. (2008) reported that aquatic and land-based exercises both improved elderlies’ balance ability (25) and both exercises had the same positive impacts on the studied indicators. In the same vein, this report is in agreement with our observation with respect to the effects of exercise on flexibility, but not regarding its effects on motor ability and general endurance. Colado et al. (2005) found no significant difference between the aquatic and land-based exercises on physiological response, heart rate, and blood lactate when both exercises continued until muscular fatigue (26). Since the aquatic and land-based exercise programs designed in the present study were not intense enough to cause muscular fatigue, the difference in physiological responses was expectable and was observed in the results.

There are several other studies that have examined the effect of either aquatic or land-based exercises on the same indices studied in the present work. A study carried out by Soori et al. (2015) revealed significantly higher motor ability in the elderly who participated in aquatic exercises than in those who did not (11). We also found that the elderly in the aquatic exercise group obtained higher motor skill scores at the post-intervention stage. Thus, these results can be considered in concordance. This consistency can be attributed to the similarity of the types of exercise programs and research populations. Findings of a study by Dokht Abdiyan et al. (2016), which reported significantly higher motor abilities in the aquatic exercise group than in the control group ( 27), were also consistent with our results. This congruence can be due to the use of aquatic exercise in both studies with the specific goal of improving the physical ability of the elderly and considering the fact that the elderly find typical exercises too difficult and unappealing and often consider them as a compulsory activity. Furthermore, because of chronic pain, fatigue, and fear of complications, the elderly are less inclined to engage in physical activities (6). Thus, diverse exercise programs, including the ones containing aquatic exercise, are likely to be more successful in attracting the elderly to physical activity.

In a study entitled as “Effect of aquatic and land-based exercise programs on the pain and motor function of weightlifters with patellofemoral pain syndrome”, Babakhani et al. (2015) found no significant differences in the motor function of two groups after eight weeks of training (28). This report was not consistent with our results. This inconsistency can be due to the differences in sample sizes and research populations. In detail, Babakhani et al. (2015) studied 20 subjects (versus 60 subjects in our study); thus, the smaller sample size in that study may have affected its internal validity and results. In addition, the subjects of that study were all suffering from patellofemoral pain syndrome, and one cannot expect one type of exercise to show significant superiority over a different type in improving the symptoms of a chronic disease in only eight weeks.

Regarding flexibility, the present study found that the elderly men who exercised in water achieved a higher mean flexibility score than those who exercised on land, but this difference was not statistically significant. Flexibility is defined as a person’s ability to move one or a group of joints smoothly and easily through an unrestricted range of motion (9, 10). Therefore, it cannot be improved easily and via short interventions. In this regard, a study by Lord et al. (1993) reported significantly enhanced flexibility in 70-year-old subjects after nine weeks of aquatic exercise (1 hour per week) (29). In this respect, this result was in line with our finding regarding flexibility. This consistency can be due to the advanced age of the subjects in both studies, as age has an inverse relationship with flexibility. The present study also indicated an inverse relationship between the elderly’s age and their flexibility, which confirms the above argument. Therefore, the lack of significant changes in the flexibility of the subjects of this study can be related to their age (60 to 78 years).

A study by Lund et al. (2008) also showed no significant difference in the muscle strength (muscle extension and flexion) of subjects who exercised in water, those who exercised on land, and a control group (32). This result is somewhat congruent with the present findings. Possible causes of this consistency are the nature of osteoarthritis and the duration of the intervention. Osteoarthritis is a type of joint inflammation or swelling that can be caused by physical injury, gout, pseudogout, psoriasis, Charcot, and hemophilia. Osteoarthritis is especially degenerative if caused by physical injury since damage to the joint ligaments causes joint instability, which leads to concentration of pressure on one part of the joint. This condition is more common in the elderly because of decreased visual acuity, reduced balance, and muscle weakness; thus, they are likely to experience motion restriction and dryness in the joints (31), which are unlikely to be alleviated with only eight weeks of exercise in water. Note that the elderly participated in the present study were not diagnosed with disease-induced motion restriction, but perhaps the 6-week intervention was not long enough to improve the flexibility of the 70-year-old subjects. Therefore, the lack of significant difference between the flexibility of aquatic and land-based exercise groups was expected.

On the other hand, Bergamin et al. (2013) reported that elderly subjects in an aquatic exercise group had significantly higher flexibility in the upper and lower extremities than those in a land-based exercise group and a control group (32). The study of Soori et al. (2015) also showed that after six weeks of exercise in water, the flexibility of their experimental group was significantly higher than that of their control group (11). Although the interventions of these two studies were of the same length as our intervention, their results were not congruent with ours. The present study measured slightly higher flexibility in the aquatic exercise group than in the land-based exercise group. This difference that can be attributed to the effects of aquatic exercise, where the elderly have better interaction with their peers, enjoy a pleasurable environment, and have more opportunity to sympathize with one another. Thus, the aquatic exercise group showed more commitment to this exercise, and therefore, developed better muscular flexibility. The mentioned commitment may also be enhanced by improved self-confidence due to performing some exercises in the deeper section of the pool (16). Research has also shown that continued aquatic exercise will make it easier to perform (33), which may be helpful for older people with diminished physical ability. This reason could account for the insignificantly higher mean flexibility score observed in the aquatic exercise group compared to the land-based exercise group.

Our findings presented a significant improvement in the mean flexibility score of both aquatic and land-based exercise groups, which can be attributed to the general effect of exercise on flexibility and quality of life (34). Although both exercise programs are effective in improving the flexibility of the elderly, the choice of the best method for enhancing flexibility should be made according to cost considerations and availability of the facilities required for the exercise.

Regarding general endurance, we found that the elderly who exercised in water had a higher post-intervention mean endurance score than those who exercised on land. In this respect, our results are consistent with the results of Soori et al. (2015) and Dokht Abdiyan et al. (2016), who reported that the elderly in their aquatic exercise groups had significantly higher general endurance than those in the respective control groups (11, 27). This similarity is probably due to the general effect of aquatic exercise on cardiovascular endurance, which enables the body to better deal with the stress of long physical activity. People who enjoy higher endurance have stronger heart muscles, lower heart rates, and higher cardiac contractility, and therefore, increased cardiac output (35), which translates into the higher ability of the heart to pump blood and nutrients to more active cells. This results in lower variations in blood pressure, which is a primary cause of myocardial infarction (19). These changes also lead to a general improvement in fitness and delayed fatigue (20).

The study of Katsural et al. (2010) on 65-year-old elderlies presented that eight weeks of aquatic exercise (three sessions a week, each session lasting 90 minutes) with an emphasis on walking in water could significantly promote strength, speed, balance, and motor ability (34). This result is consistent with our findings. Furthermore, physical activity in water allows for a wider range of movements without exposing the elderly to danger or injury and leads to improved motor ability and control over physical condition (27). When in water, the body experiences enhanced afferent stimulation from skin sensors. Thus, aquatic exercises can elevate the transmission of sensory messages to the corresponding section in the central nervous system. (27). This may boost general endurance by improving hemoglobin and blood volumes, and thereby, the amount of oxygen supply to the muscles (20). This improvement may also reduce blood lipid level and prevent clots and atherosclerosis, which are the most important causes of myocardial infarction, and enhance the performance of muscles in using blood oxygen following an increase in the mitochondrial enzymes within muscle cells. In prolonged physical activities, there is a higher tendency to use slow-twitch muscle fibers, and endurance performance depends on the ability of active muscle cells to consume oxygen and nutrients to generate energy (17, 18). All these changes lead to improved fitness and delayed fatigue (20).

One of the limitations of this study was the restriction of the sample to the elderly who visited the two health centers, which indicates that our results may not be generalizable to the elderly living in nursing homes, who were not included in the study due to lack of cooperation of these facilities.

Implications for Practice

Aquatic exercise was found to have a significantly greater impact on the biomotor ability of elderly men than did land-based exercise. Given the association of biomotor ability with general health, quality of life, and independence of the elderly, and therefore, with their performance in physical, psychological, social, and environmental dimensions, aquatic exercise can be used more effectively to improve the independence and quality of life of the elderly and their performance in the mentioned dimensions. The provided insight into the effects of different factors on the efficacy of aquatic and land-based exercises for the elderly may help the authorities to choose the method to be used in long-term programs to achieve satisfactory results with acceptable cost-efficiency. These exercise programs, which contribute to prevention, care, and rehabilitation, must be devised based on specific aging considerations and with the goal of improving the elderly’s motor mobility. Since economic woes currently limit the applicability of aquatic exercise programs for the Iranian elderly, further prolonged studies on the possible complications of land-based and aquatic exercises and the effects of these exercises on static and dynamic balance and quality of life are recommended.

Acknowledgments

This paper is part of a thesis submitted in partial fulfillment of the requirements for a Master’s degree in Geriatric Nursing. The research plan was approved in advance by the Ethics Committee of Mashhad University of Medical Sciences with the code IR.MUMS.REC94877 and was registered in Iranian Registry of Clinical Trials with the code IRCT20767018244845N3. The authors would like to express their sincere gratitude to the Research Deputy of Mashhad University of Medical Sciences for their financial support, and to all the professors at the Faculty of Nursing and Midwifery, the staff of Imamat and Daneshamuz health centers, and the elderly who volunteered to participate in this study.

Conflicts of Interest

The authors declare no conflicts of interest.